docstr: Test that acquisition function returns correct weighted acquisition
          
docstr_tok: ["Test","that","acquisition","function","returns","correct","weighted","acquisition"]
code: def test_acquisition_function(self):
      """Test that acquisition function returns correct weighted acquisition"""
      self.mock_model.predict.return_value = np.array(
          [[1, 2, 3, 4], [3, 3, 3, 3]]
      )
      self.mock_model.get_fmin.return_value = np.array(
          [[0.1, 0.2, 0.3, 0.4]]
      )
  
      weighted_acquisition = (
          self.mpi_mcmc_acquisition.acquisition_function(
              np.array([2, 2])
          )
      )
  
      expected_acquisition = np.array(
          [
              [-0.09520448, -0.09839503, -0.10161442, -0.10485931],
              [-0.09520448, -0.09839503, -0.10161442, -0.10485931],
          ]
      )
      self.assertTrue(
          np.isclose(weighted_acquisition, expected_acquisition).all()
      )
  
file_path: GPyOpt/GPyOpt/testing/acquisitions_tests/test_mpi_mcmc_acquisition.py
imports: import unittest
  import numpy
  from GPyOpt.acquisitions import AcquisitionMPI_MCMC
  from GPyOpt.core.task.space import Design_space
  from mock import Mock
label_desc: Use image node_id 2 for calling the TestMPImcmcAcquisition obj's underlying member method code with example usage: obj.test_acquisition_function() without return types